Campbell Scientific CPEC200 Closed-Path Eddy-Covariance System - Manual (Page 61)

Appendix A. CPEC200 Diagnostics
TABLE A-1. Summary CPEC200 diagnostic flags encoded in diag_cpec
Binary Bit
(LSB = 1)
Numeric
Value
Relevant?
Corresponding
public variable
(bit is set if
variable=false)
Status reported in
cpec_status
EC_mode
= True
EC_mode
= False
9 256 Yes Yes BattVolt_OK ERROR: Battery voltage is in
deadband
or
ERROR: Battery voltage is too low
8 128 Yes Yes irga_OK ERROR: IRGA problem
7 64 Yes No sonic_OK ERROR: Sonic problem
6 32 Yes No pump_flow_OK ERROR: Pump flow problem
5 16 Yes No pump_tmpr_OK ERROR: Pump temperature problem
4 8 Yes Yes buff_depth_OK WARNING: Buffer depth too large
3 4 No Yes valve_flow_OK ERROR: Valve flow problem
2 2 No Yes valve_tmprOK ERROR: Valve temperature problem
1 1 No Yes scrub_tmprOK ERROR: Scrub module temperature
problem
none 0 NA NA NA CPEC is OK
Bit 9: Battery Voltage
If diag_cpec is greater than 255, this indicates bit 9 of diag_cpec is set. To
decode other diagnostic bits, subtract 256 from diag_cpec and compare the
remainder to the bit values below.
Bit 9 of diag_cpec is equivalent to BattVolt_OK = False. It indicates the
power source for the CPEC200 has dropped below the acceptable voltage limit.
This triggers the CPEC200 to power down as much of the system as possible to
prevent a deep discharge that might damage the user’s battery. The pump,
valves, EC155 gas head, scrub module, and their associated fans, heaters and
pumps will all be powered down. The EC100 electronics and the CSAT3A
sonic head will remain powered, however. The CPEC200 will power back up
when the supply voltage reaches an acceptable level.
There are two system configuration variables; BATT_LOWLIMIT and
BATT_DEADBAND that determine the shutdown and turn-on voltage (see
Section 5.4.1, System Configuration Variables).
BattVolt_OK will be set to False if the battery voltage BattVolt falls below
the shutdown limit:
BattVolt < BATT_LOWLIMIT
Note that BattVolt_OK will remain False until the supply voltage reaches the
turn-on voltage:
BattVolt > BATT_LOWLIMIT + BATT_DEADBAND
A-9